Effect of Air Conditioning on Power/Speed?

[joebruin77]

Back when I had my Audi A4 and my Subaru WRX, if I wanted to maximize power and speed, I would shut off the air conditioning temporarily. I was curious for my P3D, does the same thing apply? If I am stopped at a red light and I want to maximize my power and speed off the line, does shutting off the AC have any noticeable effect? Will my zero to 60 time be noticeably slower if I have the AC on?

Any thoughts/comments/suggestions are appreciated.

Thank you,
joebruin77

 

[SleeperService]

Track Mode on the P3D actually turns up the AC and uses it to cool the batteries and motors, so I'm going to go with "no effect" on 0-60 times.

 

[Big Earl]

No real effect. Air conditioning on an internal combustion vehicle can steal a substantial amount of horsepower (ten or more depending on the size, age and design system).

The air conditioning system on a Tesla only draws a few kW of power from the battery at maximum output and much less at low output.

I’m not aware of anyone reporting faster 0-60 times by turning off the climate control.

 

[Kevy Baby]

With an ICE car, the compressor pump that is used for the AC uses the ICE to drive it (and it requires a fair amount of energy). In a Tesla, it is an electric motor that runs the AC, so it should not have the same hit to the drive system. Someone smarter than me can probably confirm that the electric power management is such that the AC does not affect the car's drive motors.

 

[Phlier]

In a Tesla, it is an electric motor that runs the AC,

Exactly.

And it is not the same electric motor(s) that powers the wheels. So no, you are not stealing power from the drive train to run the AC like you are in an ICE vehicle.

 

[jedi2b]

so, the AC motor and the drivetrain motor take juice from the same battery and power supply system, so in theory, there might be some incidence, as the AC might be using some current that would otherwise be available to the drivetrain.

now, in the case of most electric cars, the AC seem to consume around 500-1500 watts/hr, depending on the model. No idea in the case of a Tesla.

In the other hand, in the case of the model 3, the drivetrain motor peaks at about 211 kw/hr for the RWD (source: Tesla Model 3 - Wikipedia)

so worst case, the AC would be taking about 0.4% of total power that won't be available to the drivetrain.

compared to the 5-10% incidence on power of the AC on ICE cars, it's peanuts

 

[JulienW]

Yea it seems that if you are using 1kW to run the HVAC that is 1kW NOT available to power the motors.

 

[Phlier]

so, the AC motor and the drivetrain motor take juice from the same battery and power supply system, so in theory, there might be some incidence, as the AC might be using some current that would otherwise be available to the drivetrain.

now, in the case of most electric cars, the AC seem to consume around 500-1500 watts/hr, depending on the model. No idea in the case of a Tesla.

In the other hand, in the case of the model 3, the drivetrain motor peaks at about 211 kw/hr for the RWD (source: Tesla Model 3 - Wikipedia)

so worst case, the AC would be taking about 0.4% of total power that won't be available to the drivetrain.

compared to the 5-10% incidence on power of the AC on ICE cars, it's peanuts

Your assumption assumes that power is available on an either/or basis. That's not necessarily the case. As long as the battery has the capability to power both systems at 100%, you aren't robbing one to power the other.

 

[brkaus]

Sounds like an experiment is needed.

is the car motor/ traction limited or battery limited?

The regular and the performance version have the same battery pack, so it is very unlikely that a regular version would see any impact from the hvac.

I would bet there is no impact on any of the versions.

 

[jedi2b]

Your assumption assumes that power is available on an either/or basis. That's not necessarily the case. As long as the battery has the capability to power both systems at 100%, you aren't robbing one to power the other.

you are correct. In the other hand, making some of the battery power unavailable to the drivetrain just in case the AC is on seems like a weird design decision for a performance oriented car, hence my worst case assumption.

 

[jedi2b]

Sounds like an experiment is needed.

is the car motor/ traction limited or battery limited?

The regular and the performance version have the same battery pack, so it is very unlikely that a regular version would see any impact from the hvac.

I would bet there is no impact on any of the versions.

well, if my math above is correct, and the worst case impact is 0.4% or less, i doubt you can actually measure the difference. Tarmac temperature and wind will have much greater incidence than that, for example.

 

[Phlier]

you are correct. In the other hand, making some of the battery power unavailable to the drivetrain just in case the AC is on seems like a weird design decision for a performance oriented car, hence my worst case assumption.

Somewhere on YouTube, there is a video of a guy doing multiple 1/4 mile passes in his Tesla. Some with AC on, others with AC off. He notes no decrease in ET with AC off vs. on.... wish I had a link handy.

But that does show that the battery has the capacity/capability to run both systems at 100% simultaneously.

 

[ewoodrick]

If you are talking about acceleration from a traffic light, then absolutely no, partially because you can only accelerate for 2-3 seconds before exceeding the speed limit.

 

[Viking79]

The battery determines max power in an electric car, and has a max discharge. So the AC could cut into power, but I suspect the car will disengage it should you floor the "go pedal". Most modern gas cars disengage the AC if you accelerate hard too.

My i3 will prioritize motor power with operation, even at expense of heater or AC. In very cold weather if the battery is cold soaked and the car is in restricted power mode, the heater won't work if you are accelerating. Cold soaked at about -10 F, it took it 10 minutes to blow hot air while driving. Sitting still was fine.

Point is, yes, in theory the car will have less power available, but the car will likely prioritize motor power (I am not yet familiar with Tesla).

 

[Nocturnal]

The only time it might matter is if your battery or motors are hot and the car is pulling power. That's only going to happen on the track though.

 

[Kleenerth3]

See the video of the Tesla Super Bottle and that will explain a lot. It controls all cooling systems and uses very little energy. Quite fascinating invention. It does not affect performance, only battery life as drain on percentage.

 

[Ol'Blue]

I feel like this is a fairly moot point.

As soon as I stop accelerating, I notice the cooling system is already turned on. I suspect that if you hit full throttle it automatically turns on the AC to control the batteries.

Even reversing up my short driveway turns on the cooling system (A/C)

I don’t think you’re going to outsmart the system by turning off the HVAC.

The draw is also so little that I don’t think it’s worth the time to try to shave 0.01seconds off of the 0-60 time if it can even be defeated.


May as well just turn off the cabin fan as it’s likely to have more drain on acceleration then the A/C, then turn off the stereo, and dim the display to get the extra.

 

[Silicon Desert]

No real effect. Air conditioning on an internal combustion vehicle can steal a substantial amount of horsepower (ten or more depending on the size, age and design system).

The air conditioning system on a Tesla only draws a few kW of power from the battery at maximum output and much less at low output.

I’m not aware of anyone reporting faster 0-60 times by turning off the climate control.

yup, beat me to it. Most people relate to A/C in an ICE car stealing some power. And if I remember correctly, I think max cooling is 6kW, but I might be wrong about that.

 

[mike123abc]

I strongly suspect that the drive system even in the P model is software limited, not battery, power or motor limited. The AWD is even more limited... The RWD of course only has one motor drawing so AC is not a factor.

 

[Ol'Blue]

I strongly suspect that the drive system even in the P model is software limited, not battery, power or motor limited. The AWD is even more limited... The RWD of course only has one motor drawing so AC is not a factor.

This is a very good point I wish I had made....

This just basically killed every other point anyone else has made in this thread.